The testing of digital circuits of a device under test (DUT) while under a functional system test requires cooling of the DUT during its operation. A DUT can consume up to 200 watts of power or more during its operation. As such, dissipation and removal of the thermal energy produced during testing is essential to adequately test the DUT under normal operating conditions.
Thermal solutions currently exist for infrared optical sensor system that use air-coupled optics exclusively. For instance, diamond window heat spreaders can be used in conjunction with heat exchangers to provide optical access to a back side of a DUT during this operation while removing the thermal energy generated by the DUT. The diamond window heat spreaders use a thin sheet of diamond window material mounted to a metal heat exchanger to allow optical inspection of a DUT while the device operates under full power. Such systems are suitable for air-coupled optical inspections systems.
However, diamond window heat spreader technology is not compatible with some forms of optical imaging systems. For instance, the use of the diamond window heat spreader technology is not compatible with solid immersion lens (SIL) optical sensors. Specifically, the use of the diamond window heat spreader introduces optical aberrations when using a SIL objective lens of an SIL optical system.